Refrigerant valve

ABSTRACT

The invention relates to a refrigerant valve assembly of the type in which the actuating spindle is loaded at one of its ends by a membrane pressure element and the other end by a spring. The membrane end of the spindle is surrounded by a bellows and it is the chamber which surrounds the bellows in which the interest is. That chamber is substantially sealed from the atmosphere but a first fluid passage connects it with the atmosphere. A second fluid passage which has fluid communication with the downstream side of the valve has a Venturi insert and intersects the first fluid passage. The Venturi produces an aspirating effect which draws moisture ladened air out of the bellows chamber referred to above.

United States Patent 1 .lespersen l l REFRIGERANT VALVE [75] lnventor: Hans Jorgen Jespersen, Sonderborg,

Denmark [73] Assignee: Danioss A/S, Nordborg, Denmark [22] Filed: June 2, 1972 [2]] Appl. No.: 259,118

[30] Foreign Application Priority Data Primary Examiner-Meyer Perlin Attorney-Wayne B. Easton [57] ABSTRACT The invention relates to a refrigerant valve assembly of the type in which the actuating spindle is loaded at one of its ends by a membrane pressure element and the other end by a spring. The membrane end of the spindle is surrounded by a bellows and it is the chamber which surrounds the bellows in which the interest is. That chamber is substantially sealed from the atmosphere but a first fluid passage connects it with the atmosphere. A second fluid passage which has fluid communication with the downstream side of the valve has a Venturi insert and intersects the first fluid passage. The Venturi produces an aspirating effect which draws moisture ladened air out of the bellows chamber referred to above.

3 Claims, 2 Drawing Figures Patented Nov. 6, 1973 3,769,811

REFRIGERANT VALVE The invention relates to a valve for a refrigerant, e.g. liquid nitrogen, to be introduced into the cold storage compartment, in which valve the actuating spindle is loaded at one of its ends by a membrane pressure element and at the other by a spring, that end of the spindle presented to the membrane being surrounded by a tubular bellows, which tightly seals off the space accommodating the spindle and connected to the working chamber of the valve and which has a small area as compared with that of the membrane, and the tubular bellows is surrounded by a chamber which is largely sealed off from the surrounding atmosphere and with which is associated a flow-restricting passage extending outwards from the outlet side of the valve.

This flow restricting passage leads from the outlet side of the valve to the surrounding atmosphere by way of the largely sealed off chamber. In this way the affect of the full pressure of the refrigerant on the membrane is kept small. If moist atmospheric air penetrates into the sealedoff chamber when the valve is in the closed position, the amount of air can only be small and despite the cooling occurring in refrigerant valves cannot lead to icing, and further when the valve is next opened, the air can be discharged by the refrigerant which flows away through the flow-restricting passage.

According to the invention the performance of a refrigerant valve of this kind is further improved by an arrangement in which the flow-restricting passage leads to the surrounding atmosphere by way of a Venturi nozzle, and a connecting passage, leading to the sealedoff chamber, is provided on the suction side of the Venturi nozzle.

In this arrangement, suction pressure is set up in the Venturi nozzle when the valve is open, i.e. when refrigerant passes out to the flow-restricting passage, which suction pressure creates a vacuum in the sealed-off chamber and thus draws atmospheric air which might be moist from the sealed-off chamber. Thus an effect is achieved similar to that occurring when the sealedoff chamber is flushed with refrigerant, but a higher refrigerant pressure at the outlet side of the valve does not produce a higher pressure in the sealed-off chamber, but a lower one.

This leads to improved control characteristics, particularly when the control pressure, passed to the membrane pressure element, changes slowly oris applied by way of a long control pipe and is therefore delayed, since a control pressure which seeks to open the valve is reinforced by the suction pressure in the sealed-off chamber, which pressure is in turn dependent upon the outlet pressure of the refrigerant. There is no danger of the valve, already slightly opened, closing again under the effect produced by the outlet pressure of the refrigerant in the sealed-off chamber.

Particular advantage is achieved if the connecting passage is provided with a flow-restricting means. In this way exchange of air between thesealed-off chamber and the atmosphere can be greatly reduced. A simple construction of valve is that in which a bore leading from the sealed-off chamber to the exterior of the easing has a flow-restricting insert at its inner end, and a passage containing the Venturi nozzle runs into the bore substantially at right-angles.

The flow-restricting insert can be exchangable. In this way the particular suction pressure obtaining in the sealed-off chamber can be adapted to suit the required capacity of the valve.

It is also expedient to provide, in the flow-restricting passage a presettable nozzle element for adjusting the Venturi nozzle. This enables the suction pressure to be adjusted.

The invention will now be described in greater detail by reference to an embodiment illustrated in the drawing, in which:

FIG. 1 is a section through an arrangement in accordance with the invention, and

FIG. 2 shows a portion, on an enlarged scale, illustrating a preferred construction.

The refrigerant valve shown in FIG. 1 has a casing 1 comprising an inlet port 2 and an outlet port 3. The case is held in position by means of screws 4. A valve spindle 5 is mounted in a guide 6 solid with the casing. A closing member 7 cooperates with a valve set 8. A valve spring 9 urges the valve spindle upwards. A membrane ll of a pressure element 12 acts on the upper end of the spindle through a pressure cap 10. The pressure element can be connected byway of a union to a pipe controlling a pressure medium. This pressure element can be actuated pressostati cally or thermostatically. I

That end of the spindle 5 presented to the membrane is surrounded by a tubular bellows 13 so that a space 14 for accommodating the spindle is created, and said space communicates withthe outlet side of the valve and is tightly sealed ofi. Outside the tubular bellows is a chamber 15 which is bounded by the bellows, the membrane and parts of the casing. A flow-restricting passage 16 leads from the outlet side of the valve to a bore 17 which leads outwards. A Venturi nozzle 18 is formed at the point where the flow-restricting passage 16 runs into the bore 17. A connecting passage 19 extends from the suction side of the Venturi nozzle to the sealed-off chamber 15. This connecting passage forms an extension of the bore 17.

In FIG. 2 the same reference numerals are used as in FIG. 1 for like parts. The connecting passage 19 is contained in a flow-restricting insert .20 which is screwed into the inner end of the bore 17. The insert can be screwed through the bore 17 for removal, and can be replaced by another insert. The Venturi nozzle is formed between the seal 21 and a nozzle element 23, which contains transverse and longitudinal bores 24 and is screwed into a threaded bore 22. The Venturi effeet can be varied by screwing in or unscrewing the nozzle element 23.

When the pressure in the pressure element 12 is too low, the valve is in the closed position as illustrated. When the control pressure rises the valve opens and liquid refrigerant is discharged through the port 3. The pressure of the refrigerant is also applied in the interior of the tubular bellows 13. Since the area of the bellows is approximately one-twelfth of that of the membrane, this opposite force has only a slight effect. A small portion of the liquid refrigerant is discharged through the flow-restricting passage 16 and the Venturi nozzle 18 as well as through the bore 17. As this occurs, a vacuum is created upstream of the Venturi nozzle and said vacuum leads to reduction of the pressure in the sealedoff chamber 15. This drop in pressure reinforces the opening movement of the valve. At the same time any moist atmospheric air that may have penetrated into the chamber 15 is drawn off. The drop in pressure also facilitates the vaporization of any moisture that may have been deposited. When the valve closes the pressure on the outlet side of the valve drops, whereas the pressure in the chamber adjusts to the pressure of the surrounding atmosphere. As this takes place, at most only slight quantities of atmospheric air can pass through the bore 17 and the connecting passage 19 into the chamber 15 and this air is drawn out again when the valve next opens.

I claim:

1. A refrigerant valve assembly comprising a casing having inlet and outlet ports and a control port, a diaphragm in said casing defining a chamber having fluid communication with said control port, a valve seat, a valve cooperable with said seat and having a spindle, spring means biasing said valve in a closing direction, a piston member attached to said membrane and forming an expansible chamber with said casing, said spindle extending into said expansible chamber and having contact with said piston member, a bellows in said expansible chamber surrounding said spindle, a first fluid passage providing fluid communication between said expansible chamber and the surrounding atmosphere, a second fluid passage intersecting said first fluid passage and having fluid communication with said outlet port on the downstream side of said valve seat, said second fluid passage having Venturi nozzle means.

2. A refrigerant valve assembly according to claim 1 in which said first fluid passage has flow restricting means.

3. A refrigerant valve assembly according to claim 1 in which said second fluid passage is normal to said first fluid passage. 

1. A refrigerant valve assembly comprising a casing having inlet and outlet ports and a control port, a diaphragm in said casing defining a chamber having fluid communication with said control port, a valve seat, a valve cooperable with said seat and having a spindle, spring means biasing said valve in a closing direction, a piston member attached to said membrane and forming an expansible chamber with said casing, said spindle extending into said expansible chamber and having contact with said piston member, a bellows in said expansible chamber surrounding said spindle, a first fluid passage providing fluid communication between said expansible chamber and the surrounding atmosphere, a second fluid passage intersecting said first fluid passage and having fluid communication with said outlet port on the downstream side of said valve seat, said second fluid passage having Venturi nozzle means.
 2. A refrigerant valve assembly according to claim 1 in which said first fluid passage has flow restricting means.
 3. A refrigerant valve assembly according to claim 1 in which said second fluid passage is normal to said first fluid passage. 